First of all Agile must be undestanding. Agile is not a method, Agile is not a process, Agile is not IT or softwre related only, Agile did not start with the Manifresto. So Agile can be used with any type of process, method, model to do anything. For example to create a software product. But returning to software (I was part of the genesis of Agile in software and non softwre field) you can find your answers by reading and understanding the Manifresto. Obviously then is up to you how to put all this stuff in practice. For example, by using some methods like SCRUM or DSDM.
(Here comes a great article about Agile genesis:https://www.linkedin.com/pulse/when-agile-...-title-publish, and and article to understand what Agile is in general:http://www.pmnetwork-digital.com/pmnetwork/april_2016?pg=73#pg73)Saving Changes...